The present invention relates to an apparatus for singling sheet goods, in particular bank notes, checks and the like, having a suction device for sucking sheet goods to be transported.
An apparatus for singling sheet goods can be provided, for example, in an apparatus for processing sheet goods, such as an automatic teller machine or a bank-note processing apparatus, to single sheet goods of a sheet-goods stack. The singling apparatus can be configured as a singling roller which comprises a first section in the form of a substantially cylindrical stator and a second section in the form of a rotor which rotates around the stator. The stator has at least one opening which is subjected to a vacuum. The opening of the stator can extend along the length of the stator and over a certain aperture angle in circumferential direction, which can extend from an opening edge. The rotor likewise has at least one opening, usually a plurality of openings or bores, which during the rotation of the rotor around the stator overlap with the opening of the stator and thereby define an opening area. A suction area is thereby formed in the circumferential direction, in which sheet goods to be singled are sucked and drawn from a sheet-goods stack. Here, the singler acts like a kind of rotary slide valve to suck sheet goods into the suction area. Such an apparatus for singling sheet goods is known for example from DE 199 53 968 A1.
When the openings of the rotor move past the opening edge of the stator, i.e. at a first end of the opening area at which the openings of the rotor and the opening of the stator begin to overlap, an opening bang from the applied vacuum and the abrupt opening arises. Reducing the resulting noise by slanting the opening edge relative to the longitudinal axis is already known from DE 199 53 968 A1, because the openings of the rotor do not all simultaneously hit the opening edge of the stator. A similar effect can be attained by an offset arrangement of the openings of the rotor. In order to reduce the noise, it is proposed in DE 199 53 968 A1 to relocate the first end of the opening area to an already exposed area after passing a guiding device to avoid additional swirls generated by the vacuum.